@AA, what development tools out there allow for direct interfacing with the Next via the UART? Are these “direct to memory writing” tools? If not, what methods would they interface with? Cheers.

Yes they are direct to memory although not available in a form like a dot command which would make it most easily accessible.

There is a bespoke system by kev brady and a system used by the pc zeus assembler. In the latter, a program or game under development checks the uart once in a while for commands from the pc. These commands include things like loading into memory so that the developer can do his thing on the pc and the game under dev can update itself.

The uart being used is normally connected to the esp wifi and the pins are only accessible internally which is fine for the current board only.

Ah ok, you're referring to the instructions Kev provided us with further up in this thread. Great, ok, thank you. I'm just re-iterating this in here for anyone seeking this information in the future. Cheers.